Posted
by
CmdrTacoon Monday December 10, 2007 @01:24PM
from the something-about-tigger-goes-here dept.

inghamb87 writes "The way water striders walk on water was discovered years ago. The insect uses its long legs to help evenly distribute its tiny body weight. The weight is distributed over a large area so that the fragile skin formed by surface tension supports the bug on the water. However, the ability of water striders to jump onto water without sinking has baffled scientists, until now." If nothing less, you need to see the picture: it's awesome.

Are you saying that these are talents jews have, including yourself and Jesus? Cool! By converting to judaism, can others get these talents, or does it only pass from the mother? Right now all I can do is turn wine into water. That's what I love about diversity: you get to learn all sorts of interesting things about other cultures and races. I wonder what other powers people are keeping secret...

By converting to judaism, can others get these talents, or does it only pass from the mother?

I think the prerequisites for that prestige class are a lot more strict... Besides the (racial?) requirements, you probably need some divine feats... not to mention the strict alignment restrictions...

I think his point is that as a Jew, implying that Jesus' miracles were "mind-tricks" at best and total BS at worst beats the alternative that they actually killed the Messiah.

Sorry for the totally off topic post but that kinda drives me crazy when Christians blame the Jews for killing Jesus. Of course they killed him because they were ALL Jewish - including Jesus. The Jewish leaders had him killed for sacrelige, very much like the Christian leaders in the dark ages had fellow Christians killed for simila

I do keep hollywood in mind. Since Jesus used this technology, I now expect a "When Jesus Attacks" to be put on the air, since there is currently a writers strike. Boards below the water is so low tech... a Mech Warrior Jesus Christ is much more interesting to be made into a movie...

Lol, that reminded me of a George Carlin sketch, in which, while narrating Jesus, he describes one of his diciples who got jealous and tried to invent some water walking shoes, with hillarious results.

I'm gonna take a guess to say that you learned this from Mr. Wizard [mrwizardstudios.com]?

I remember this episode well - it is a simple but very awe-inspiring (at least from a geek's perspective) experiment. It goes like this:

1) Fill a cookie tray with water
2) Pepper the top of the water in order to *see* the movements of the surface tension
3) Carefully place a small amount of soap in the center of the tray
4) Watch the pepper scatter to the edges of the pan as the tension breaks

If you have a kid, then you need to go do this experiment with them NOW!

RIP Don Herbert [npr.org] - you are one of the main reasons that I am a geek today.

IIRC, he used lycopodium powder on the surface. Not quite sure why that stuck in my brain for the last 20 years.

And yes, I think a lot of us owe our geekness to Mr Wizard. Off the top of my head, I remember the water displacement in the blue barrel with the kid who was freezing, the snow melting in the microwave, the telescope, the papercutting and jumping through it, the illusion of fading into a skeleton, and one of those shorts in it where they heated the pebbles to provide better traction on ice.

IIRC, he used lycopodium powder on the surface. Not quite sure why that stuck in my brain for the last 20 years.

I know why it is stuck in mine: he used it in several experiments, both with water and also to simulate a grain mill explosion. And I'd watched the same episodes repeat countless times on Nickelodeon back when it didn't have commercials other than for shows on the network (listing air times in four timezones).

I don't recall him ever using the word "hydrophobic", but I think he did say "meniscus" once.

Create a "boat" out of aluminum foil. Shape it like a square with a triangle appended to one edge, and fold slightly. Cut a small slit on the back of it (opposite the point), and place carefully on the surface of the pan filled with water. Carefully place a small drop of dish soap onto the slit, and watch the surface tension propel your boat forward!

I learned this one in high school.Take a small pitri dish or something similar and fill with milk.Place drops of several colors of food coloring in different areas.Place a drop or 2 of dishsoap in the middle.Watch the colors swirl all around as the soap reduces the surface tension.

1) Fill a cookie tray with water
2) Pepper the top of the water in order to *see* the movements of the surface tension
3) Carefully place a small amount of soap in the center of the tray
4) Watch the pepper scatter to the edges of the pan as the tension breaks

I personally learned this one from my photo tech class in high school (do they still have that class anymore?). There was a chemical that we dipped our developed and fixed film in to prevent water spots from forming on them as they dried. Water just ran right off onto the floor. My teacher casually brought up soap when explaining how this works. Ah, soap! I knew it had a use;^)

We're working on it - it should be responsive now. After a few friendly suggestions, they've installed WP-Cache on their site, and they've also been advised to submit static HTML pages in links to/. and Digg, or use Coral Cache.

MIT researchers report in the Aug. 7 issue of Nature that they now understand how the insects known as water striders skim effortlessly across the surface of ponds and oceans.

And:

Using mathematics, high-speed photography and a variety of flow visualization techniques, Bush, mathematics graduate student David L. Hu and mechanical engineering graduate student Brian Chan uncovered the true way in which water striders walk on water.

As the insect rests on the surface, the tips of its thin legs create miniscule valleys. It sculls the middle set of its three pairs of legs like oars, causing the water behind those legs to propel it forward as the surface of the valley rebounds like a trampoline.
Although the rowing motion does create tiny waves, "the waves do not play a significant role in the momentum transfer necessary for propulsion," the researchers wrote. "The momentum transfer is primarily in the form of subsurface vortices."

Article Content (even Google cache is REALLY slow):The way water striders walk on water was discovered years ago. The insect uses its long legs to help evenly distribute its tiny body weight. The weight is distributed over a large area so that the fragile skin formed by surface tension supports the bug on the water. However, the ability of water striders to jump onto water without sinking has baffled scientists, until now.

A team of researchers at Seoul National University, led by Ho-Young Kim and Duck-Gyu L

A team of researchers at Seoul National University, led by Ho-Young Kim and Duck-Gyu Lee, has finally answered that question. By using a highly water-repellent sphere, which mimicked the actions of the water strider's highly water-repellent legs, they were able to determine a small range of speeds at which the sphere or insect could hit the water and not sink.

I managed to view the site before it went down in flames under the slashdot effect. The picture was cool, but the article left much to be desired:

How big is the robot?
How much does it weigh?
How fast can it move?
How is it controlled?
What is the range of speeds for this that was mentioned in the article?
They mentioned applying it to sampling water quality, but wouldn't that disrupt the surface tension to sample the water right under the robot?

This one is erroneous in at least one way. It suggests that tiny bubbles trapped in hairs on the bug's legs make it float. Tosh! The bubbles are too small to make it boyant. What the bubbles do is increase the surface area which, in turn, increases the amount of surface tension "skin" that the bug walks on and therefore the carrying capacity.

As most fly fishermen would tell you, surface tension is far stronger than you'd think. Hatching bugs struggle to get through the surface tension which keeps them under the surface. Once they break through they are able to sit and walk quite easily.

Never put a line like this in a/. summary. Do you want Congress to pass a law classifying/. as some kind of cyber-terror weapon? You can almost see smoke coming out of the ground around these poor bastards' data center.

The traffic isn't that bad. We just had to talk to them a bit about caches and linking directly to dynamic pages. We also temporarily raised the caps on their virtual server and adjusted the Apache configuration for this type of traffic.

I applaud your attention and help to your customer(s). I would most certainly prefer to work with someone who can help deal with surges, DDOS, rootkits, and the many other problems that plague web sites. My hat is off to you.

I remember going to a conference presentation by John Bush [mit.edu] back in 2005 which detailed the physics behind water striders. His presentation was very good, and the video footage he presented was absolutely fantastic (see here [mit.edu] and here [mit.edu]).
I think the work referenced in the main article isn't quite as groundbreaking as they'd have you believe. There has been quite a lot of work in this area over the last five years.

Now all we need is worm-like robots that burrow through the earth. And of course earwhig robots that burrow into your ear, and tick robots that attach to your skin and suck your blood. Cock roach robots won't need to do anything except run around and freak people out because they're so icky. Then, without a shot being fired, hasta la vista Sarah Conner.

Last week, Oak Ridge announced development of a material that is virtually unwettable [ornl.gov], a nanoetched powder that acts on surface tension and can be applied as a coating to almost any surface. A boat with a coated hull would become a water strider - one continuous stride. Much cooler news than this article.

Some how I think this robot will be marketed for evangelical [newgrounds.com] purposes. And for that reason IT MUST BE DESTROYED!

*In the voice of that BS Billy Graham book advert*Have you ever wondered why God never allowed for you to have the rich fullfilling life you think deserve? Are you tired of waiting for the rapture for God to smite democrats, Catholics, Muslims, people who hate George Bush, teachers who teach Darwinism, the Internet, and everyone else except for you and all your elitist God-fearing friends?Intro

I have trouble disagreeing with you. I looked at the pic expecting a robot analog of a water strider. Instead it was really disappointing. You can get the same exact effect using a common paper clip on a cup of water! Maybe I can attach a small motor to it and call it a water bouncing robot. I got to tell you man, these scientists are seriously making the 21st century suck.

It's science for the headlines. NASA pioneered it by sending humans where robots should go, albeit at a time when it was appropriate (space race). Remember these assholes? [slashdot.org] Making up 2.5 meter scorpions from a 46 centimeter claw. Assuming the claw-body ratio of modern scorpions, that would still make for an impressive 1.75 meter scorpion. But no, these idiots had to exaggerate, to break records. Science is being perverted. Bah.

Of all the so-called sciences, paleontology has to be the most contrived.

Modern scorpions do not have a fixed claw-to-body ratio. Non-poisonous scorpions tend to have larger more powerful claws, sometimes by a factor of 3 or more. Using modern claw to body ratios would give a size of somewhere between approx 1.5 and 5 metres. Of course that assumes that claw-to-body ratios have been constant over time.

One just needs to look at the fiddler crab to see how stupid it is to make claw-to-body comparisons and suc

Of course it's fucking science, even if it isn't exactly what you hoped it would be. What makes this "not science"?!

The "robot" spreads its weight out using the whole length of its legs in contact with the water. That is nothing like a water strider.

So? So our robots aren't nearly as light as a water strider (I guarantee you the robot pictured weights a lot more than 15x a water strider), and require much greater surface area to stay afloat. Also we can't create legs with the tiny micro-hairs that allow the strider to stay afloat and jump on water so easily. What do you know, nature still wins, and we still have a lot of work to do to duplicate it.

If that's the standard, pretty much all science is bullshit.

The only similarity is that they both use surface tension.

Well according to your link water striders don't even rely on surface tension.

Nevertheless: Water-walking robot. Some people would think that's cool. But that would be those of us who appreciate advancements in the state of the art, not those who think anything less than the end goal is a 'crock of shit'.

So if the robot is 15x the weight of a strider, they might as well just take off the legs and put the rest on a real strider.

Yeah, that's why I said the robot clearly weights a lot more than 15x a water strider. Look at it, it's a block of metal. It's much more dense and vastly larger than a water strider -- not surprising given the state of robotics. There's no possible way a water strider could hold up that robotic body, it's not even within an order of magnitude of being capable.

The "robot" spreads its weight out using the whole length of its legs in contact with the water. That is nothing like a water strider.

The real strider does a quite similar thing with a length of its leg horizontal to the water. [dinosaurtheory.com] I can't fathom how you think this is nothing like that. It just has a higher percent of the leg horizontal in contact with the water because the body of the robot weighs more and the legs need to support more weight.